Some systems are configured to use a programmable controller (PLC). When such a system is constructed, the user can use a system construction support apparatus. With the system construction support apparatus, the user can generate a system configuration diagram illustrating the connection relationships between apparatuses by arranging displayed objects corresponding to the apparatuses (PLC, display, and apparatuses controlled by PLC) from which the system is configured at desired positions on the screen and connecting the displayed objects with each other. The user can generate the system configuration diagram simulating the system to be constructed in the system construction support apparatus and can examine, in advance, the apparatuses to be selected and the setting information on the apparatuses.
The setting information set in the PLC includes a control program of the PLC. It is conventional for the user to create a control program in which the real addresses, which are referred to as devices, are directly specified by device numbers. Meanwhile, it has recently become possible to modularize a control program by creating the control program using variables referred to as labels and assigning devices to the labels (see, for example, Patent Literature 1).